Why would Palin be concerned about O’Donnell also speaking there?
Only two reasons I can imagine would be to avoid offending Karl Rove (why in the world would anyone not want Karl Rove offended?)
Or because of some inherent opposition to free speech.
Neither seems real likely...
From past experience, this is exactly the sort of rumor which gets (rapidly) swatted down directly by Governor Palin.
Should be clearer in an hour or so.
Because O'Donnell is a flake and nobody even considering running for President would want to be on the same stage as her.